I use Azureus as well... i don't think there is much difference between the 2, quality wise.

Its just that Azureus has different windows for up and downloads, which i defo like better to keep em apart.. Azureus gives me faster downloads, like 800 KB/sec .. but Azureus takes a bit more system resources then U torrent.. but with a modern fast machine you will not notice much of that, me gathers. However.. it could be a reason to switch.. indeed.

Just my opinion.